Method of extending biomass conversion catalyst life

Abstract

A method of extending the catalyst life of a hydrogenolysis catalyst activity in the presence of biomass and aqueous solution is described. Lignocellulosic biomass solids and aqueous solution is provided to in a hydrothermal digestion unit in the presence of a digestive solvent, and a supported hydrogenolysis catalyst containing (a) sulfur, (b) Mo or W, and (c) Co, Ni or mixture thereof, incorporated into a solid metal oxide support. The lignocellulosic biomass solids in the hydrothermal digestion unit is heated to a temperature in the range of 180° C. to less than 300° C. in the presence of digestive solvent, hydrogen, and in the range of 0.15 wt. % to 12.5 wt. %, based on catalyst, of H 2 S or H 2 S source at least partially soluble in aqueous solution, and the supported hydrogenolysis catalyst forming a product solution containing plurality of oxygenated hydrocarbons, the hydrothermal digestion unit maintaining protective sulfur concentration.

We claim: 
     
       1. A method of extending the catalyst life of a hydrogenolysis catalyst activity in the presence of biomass and aqueous solution comprising: (i) providing lignocellulosic biomass solids and aqueous solution in a hydrothermal digestion unit in the presence of a digestive solvent, and a supported hydrogenolysis catalyst containing (a) sulfur, (b) Mo or W, and (c) Co, Ni or mixture thereof, incorporated into a solid metal oxide support; (ii) heating the lignocellulosic biomass solids in the hydrothermal digestion unit to a temperature in the range of 180° C. to less than 300° C. in the presence of digestive solvent, hydrogen, and in the range of 0.15 wt. % to 12.5 wt. %, based on catalyst, of H 2 S or H 2 S source at least partially soluble in aqueous solution, and the supported hydrogenolysis catalyst thereby forming a product solution containing plurality of oxygenated hydrocarbons, said hydrothermal digestion unit maintaining protective sulfur concentration. 
     
     
       2. The method of  claim 1  wherein the residence time of the hydrothermal digestion unit (Vol/Feed) is in the range of 0.5 to 20 h. 
     
     
       3. The method of  claim 1  wherein the H 2 S source comprises at least one of SO 2 , dimethylsulfoxide, cysteine, dimethylsulfide, dimethyldisulfide, N-butylmercaptan, tertiarybutyl polysulfide, sodium sulfide, sodium thiosulfate, and di-tert-butyl polysulfide. 
     
     
       4. The method of  claim 1  wherein H 2 S and/or a gaseous H 2 S source is added to H 2  stream inlet. 
     
     
       5. The method of  claim 4  wherein H 2 S and/or SO 2  is added to H 2  stream inlet. 
     
     
       6. The method of  claim 1  wherein at least a portion of the product solution is recycled to the hydrothermal digestion unit via a liquid recycle stream. 
     
     
       7. The method of  claim 1  wherein at least one of dimethyl sulfoxide, dimethyl sulfide, dimethyldisulfide, n-butylmercaptan, teriarybutylpolysulfide, cysteine is added to the liquid recycle stream. 
     
     
       8. The method of  claim 1  wherein further monitoring the H 2 S level in the gas phase in the hydrothermal digestion unit and adjusting the addition of H 2 S or H 2 S source to maintain H 2 S partial pressure or protective sulfur concentration in the hydrothermal digestion unit. 
     
     
       9. The method of  claim 1  wherein H 2 S source is DMSO. 
     
     
       10. The method of  claim 1  wherein H 2 S source is cysteine. 
     
     
       11. The method of  claim 1  wherein H 2 S or H 2 S source or protective sulfur is recycled to the hydrothermal digestion unit. 
     
     
       12. The method of  claim 1  wherein H 2 S or H 2 S source is present in the range of 0.15 to 10 wt. % based on catalyst. 
     
     
       13. The method of  claim 12  wherein H 2 S or H 2 S source is present in the range of 0.15 to 5 wt. %, based on catalyst. 
     
     
       14. The method of  claim 2  wherein H 2 S or H 2 S source or protective sulfur is recycled to the hydrothermal digestion unit. 
     
     
       15. The method of  claim 8  wherein H 2 S or H 2 S source or protective sulfur is recycled to the hydrothermal digestion unit. 
     
     
       16. The method of  claim 15  wherein at least a portion of the product solution is recycled to the hydrothermal digestion unit via a liquid recycle stream. 
     
     
       17. The method of  claim 8  wherein H 2 S and/or a gaseous H 2 S source is added to H 2  stream inlet. 
     
     
       18. The method of  claim 17  wherein H 2 S and/or SO 2  is added to H 2  stream inlet.